1. Field of the Invention
The present invention relates to an ice making device, installed in a refrigerator, for supplying ice cubes made to a ice storage container when the ice cubes are insufficient in the container, and a method of controlling an ice making device thus functions.
2. Related Art
Recently, a home-use refrigerator with an automatic ice making device has been sold in market. A drive device is used for driving the automatic ice making device of the refrigerator. One of the known drive devices is disclosed in JP-A-9-264646. In this device, an ice detecting arm for detecting an amount of ice cubes in the ice storage container is operated by an AC motor or a DC motor. In most cases, the ice detecting arm is driven by use of a cam face of a cam gear as described in the publication stated above.
The cam gear has at least three positions; an ice making position where the ice detecting arm is put in a stand-by place, an ice detecting position for detecting as to if the ice storage container is full of ice cubes, and an ice separation position for separating ice cubes from the ice tray in co-action with a twist of the tray, and put them into the ice storage container.
When the cam gear is rotated, the ice detecting arm is vertically moved to detect an amount of ice cubes in the container. Through the detecting operation, to check the current position of the ice detecting arm, three signals are respectively generated at the ice making position, the full-ice position and the ice separation position. The motor for driving the ice detecting arm is controlled in on/off and its rotation direction in accordance with those signals. A Hall IC device or a switch device is used for generating those signals.
The conventional ice making device is designed such that the angular control of the ice tray is impossible by use of only the DC motor. For this reason, one Hall IC device as an origin sensor is used commonly for sensing the ice separation position, the ice making position and the ice detecting position. Where the water supply position is different from the ice making position, it is very difficult to control the ice making device because of the use of one sensor. For example, where the water supply position is located at a position slightly shifted to a region not including the ice separation position, the single sensor must take a role of a water supply position sensor, in addition to the sensors for the origin, ice separation position, ice making position, and ice detecting position. The control for searching for an origin point in an initial stage after the power-on of the device is difficult.
When the origin searching is performed, if the ice tray reaches the water supply position, water is automatically supplied to the ice tray since the mechanism is so constructed. Therefore, it is necessary to design the ice making device so that the ice tray is not moved to the water supply position in the initial stage. When one sensor having a multiple of functions is used, such a design is very difficult.
In a conventional method of controlling the ice making device, the tray is thrust upon a mechanical locking position located in a region including the ice making position, in the initializing mode of the ice making device. With this, if the ice tray is turned (reversely) beyond the ice making position, and the water supplying operation is performed, the water is supplied to the ice tray and is mechanically locked even in the initializing mode. This should be avoided. In the conventional control method where the ice tray is slightly turned beyond the ice making position in the reverse direction and mechanically locked, the water supplying operation, which should be avoided in the initializing mode, is automatically performed in this mode.
A method of controlling an ice making device is disclosed in JP-A-9-26464. In this method, the tray is always mechanically locked in the initializing mode. Therefore, every time the device is initialized, the cam gear hits a protrusion of the case to generate vibration and impact sound. Those sounds a little jar so that user's nerves negligible in daytime, but these are noisy in the quiet place at night. The user may mistake the refrigerator as the defective one. This will reduce the product quality of the refrigerator.